Condenser plate structure and mounting



Oct. 18, 1960 J. E. JENNINGS ETAL 2,957,113

connsnssa PLATE smuc'ruaz AND MOUNTING Original Filed Nov. 24, 1951 /NVE N TORS JO EMME TT JENNINGS LEW/8 B. STEWARD their ATTORNEY United States Patent CONDENSER PLATE STRUCTURE AND MOUNTING Jo Emmett Jennings and Lewis B. Steward, San Jose, Calif., assignors, by mesue assignments, to Jennings Radio Manufacturing Corporation, San Jose, Calif., a corporation of California Continuation of application Ser. No. 258,012, Nov. 24, 1951. This application Oct. 8, 1957, Ser. No. 689,007

3 Claims. (Cl. 317245) Our invention relates to the construction and mounting of condenser plates; and this application is a continuation of our copending application Serial Number 258,012, filed November 24, 1951, now abandoned, which is a continuation-in-part of our copending application Serial Number 128,438, filed November 19, 1949, and now abandoned.

The object of the invention is the provision of an assembly of concentric cylindrical condenser plates and a mounting structure, possessed of a high degree of accuracy and rigidity.

Another object is the provision of a construction of condenser plates and mounting means peculiarly suitable to the use of nickel.

The application possesses other objects which will be explained in the following description of the embodiment illustrated in the drawings. Our invention is not limited to the embodiment shown since it may be embodied in a plurality of forms as set forth in the claims.

Referring to the drawings:

Fig. 1 is an elevation of our vacuum variable condenser, partly in vertical section through the plates and plate mounting.

Fig. 2 is a vertical half sectional view of a portion of the condenser plates and mounting sectioned in Fig. l, but on a larger scale than shown in Fig. 1.

Fig. 3 is a plan view of the assembly of the condenser plates on the back plate, a portion of the back plate being cut away to disclose the spaced flanges of the condenser plates as shown.

One of the primary requirements in the building of a condenser such as that illustrated in the drawings, is the designing of the parts for ready and reasonably low cost assembly into a sturdy structure possessed of requisite mechanical precision and with the desired electrical characteristics. In the following description we have treated our condenser as it is made with nickel plates and nickel mounting parts.

We have found the best approach to solution of such a problem, to be the adoption of a cylindrical motif for nearly all the parts, which are arranged with reference to a central axis. Such parts lend themselves most easily to precision manufacture and assembly into the complete unit.

Referring first .to Fig. 1, the vacuumized shell or envelope of our condenser includes a cylindrical copper end cap 2 of relatively large diameter, and joined by a vacuum tight metal-to-glass seal 3 to the glass cylinder 4, which at the other end is joined by the seal 6 to the copper end cap 7. The bulge 8 around the middle of the glass cylinder marks the location of the joint between the two halves of the cylinder. It will be understood that cooperating parts of the condenser are assembled in each half, and the halves then coalesced along their free edges to form the complete envelope or shell shown in Fig. 1.

Snugly fitting into the end cap 2 is a nickel cylindrical mounting shell 9. An internally extending bead 10 is formed near the end of the tubular shell as shown; and

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the external annular groove thus formed is filled with a' silver solder wire before the shell is pushed into place in the copper cap. Subsequent heating brazes the two parts together, the solder running throughout the joint between cap and shell to unite the two in a rigid structure. The projecting free end of the shell is turned outwardly to form a radial flange 12, carrying the cylindrical flange 23. This double flange formation not only aids in preserving the cylindrical integrity of the part, but also forms a secure and concentric seat for mounting the fixed nickel plates of the condenser.

In the flanged open end of the nickel mounting shell 9, the unit assembly of fixed condenser plates 14 is disposed. The plates are cylindrical nickel shells arranged concentrically; and it is to be noted that the largest of the shells is substantially the same diameter as the mounting shell 9, which thus provides a broad, stable base for the condenser plate shells.

Each of the plate shells 14 is formed by cutting to size nickel sheet material of suitable gauge, and rolling it into a cylinder. It is then seam-welded at the contiguous edges and shaped on one open end by a spinning operation to form thereon a short inwardly extending radial flange 16. The assembly of shells of successively smaller diameters are held in a jig, spaced apart at the desired distance and in true concentricity, with the radial flange of each one flat against a back plate 17. The flange of each shell is then integrally united to the back plate by spot welding, the welds 18 being closely spaced in a circle midway of the width of the flange as shown in Fig. 3.

After the fixed condenser plates have been Welded to the base plate, the assembly is placed in the flanged seat 12-13 of the tubular mounting shell to provide a closed inner end well thereon and integrally united therewith by a series of closely spaced welds around the flange 13. Thus is formed an exceedingly rigid integral structure, with a high degree of accuracy of spacing about the concentric axis and capable of rapid assembly with attendant reduction in costs.

The importance of concentric accuracy and of structural stability is very great because the movable plates 21 of the condenser are interleaved between the fixed plates and the spacing between the plates may be measured in but a few thousandths of an inch.

The movable plates are of course different in diameter from the fixed plates, but are formed in the same Way with radial flanges 22, and are then assembled in a jig and spot welded to a back plate 23. That assembly is placed in the flange seat 24-25 of the mounting shell 26, and welded therein through the flange 25, the procedure and structure of condenser plates, back plate, flanged seat and mounting shell being substantially the same as for the fixed plates previously described, except that the mounting shell 26 is conical while the mounting shell 9 is cylindrical.

Spot welding the back plates to their respective mounting shells along their outer peripheral edges as shown, leaves the outer surface of each plate on the side opposite the condenser plates free and unobstructed. Since each back plate is the only structure that integrally unites the spaced condenser plates, it functions to collect heat from all the connected condenser plates, and to conduct and radiate it to the broad surfaces of the relatively cool outer end caps or walls of the envelope. The radiating function is thus important because it materially aids the conductive function in maintaining each back plate at a lower temperature than the condenser plates, thus insuring a most efiicient exchange of heat from the sources of generation to the areas of dissipation.

The small closed end of the conical mounting shell 26 is formed with an annular bead 27 within which the mobile end 28 of the copper bellows 29 is brazed. The bead provides an accurate seat for the bellows end, and also adds stability and strength to the mounting shell which prevents vibration and distortion. Both mounting shells 9 and 26 are provided with holes 31 as shown, to permit easy cleaning and prevent trapping of reaction products and air in pockets'that would prevent complete evacuation.

Because of physical limitations in the drawing, the plates of the condenser are necessarily shown with a degree of thickness and as spaced apart a considerable distance. Actually they are very thin and very close together for reasons relating to the capacity of the condenser; and unless great rigidity and a high degree of accuracy in mounting and in movement is attained, objectionable changes in electrical characteristics and capacity of the instrument or even shorting across the plates is inevitable.

The fixed end 32 of the bellows is integrally united by brazing with the adjacent portion of the end cap 7 to complete the vacuumized chamber in which the condenser plates lie. The remaining parts of the condenser are shown and described in our copending application Serial No. 257,392, filed November 20, 1951, now US. Patent 2,740,926, issued April 3, 1956.

It will be noted from the above description that a structure of great rigidity and stability results. It is also apparent that there is provided extensive metallic conductors having free radiating surfaces for the flow of heat to broad external surfaces Where it may be radiated into the air.

New and extremely valuable results flow from the structure shown and explained. The rapid conduction and radiation of heat from the condenser plates by way of the back plates which form the end walls of the mounting shells, and then through the mounting shells to the end caps of the envelope is one of these results; The free flow of current without significant induction or other losses is a. second highly desirable result. 'The effects of high heat on conductivity in a conductor are well known, as are also the losses due to the conversion into heat of energy from heavy currents' These mutually created losses are minimized in our structure. A third valuable result comes from the rigidity of the mounting of our condenser plates, since it prevents vibration. This makes it possible to use many more plates set much closer together, so that a capacity results which is vastly greater than any other known condenser of comparable dimen- $10118.

In use, an electrostatic field is set up between the plates which causes a heavy alternating pull 'on the plates in synchronism with the cycle frequency. This tends to cause a physical vibration which if not kept within rigid control, can cause shorting of the condenser, and thereby ruin it. It is one of the most important features of our construction, that this destructive vibration is reduced to a minimum, and a high degree of stability, efficiency and ruggedness obtained in a relatively small unit.

' We claim:

1. In a condenser having a vacuumized envelope, a metallic hollow end cap constituting the end wall of the evacuated envelope and an external terminal electrode 'of the condenser, said end cap having a peripheral internal surface extending longitudinally of said condenser, a metallic rigid mounting shell having one end thereof provided with an outer surface in coextensive peripheral contact with and integrally secured to the internal surface of said end cap; said mounting shell having a free hollow portion extending into said envelope and terminating in an annular seat consisting of a laterally extending flange portion having a supporting lowermost surface transversely disposed in said envelope and a depending flange portion integral with the outer edge of said lateral flange and having an inner supporting surface extending longitudinally in said envelope, a base plate having a peripheral edge and a free heatradiating surface facing the hollow portion of said shell and extending fully thereacross, said base plate having the marginal edge portion of said free surface in contact with and integrally secured to the supporting lower surface of said laterally extending flange portion of said annular seat and the peripheral edge of said base plate coextensively in contact with the inner supporting surface of said depending'flange portion, and a plurality of concentrically spaced cylindrical plates integrally united to said base plate on the surface thereof opposite the free surface of said base plate.

2. In a condenser as set forth in claim 1, a plurality of concentrically spaced cylindrical plates supported on the surface of said base plate opposite the free surface of said base plate, each of said cylindrical plates having a laterally inwardly extending integral flange portion having an uppermost surface supported on 'and secured to the surface of said base plateopposite said free surface thereof, said cylindrical plates including an outermost cylindrical plate having an outermost surface adjacent said inwardly extending flange, said outermost surface of said outermost cylindrical plate being coextensively in contact with and secured to the inner supporting surface of said depending flange portion of said annular seat.

3. In a condenser having a vacuumized envelope, a metallic hollow end cap constituting the end Wall of the evacuated envelope and an external terminal electrode of the condenser, a conical metallic rigid mounting shell having the free enlarged hollow end portion extending into said envelope and terminating in an annular seat consisting of a laterally extending flange portion having a supporting surface transversely disposed in said envelope and a depending flange portion integral with the outer edge of said lateral flange and having an inner supporting surface extending longitudinally in said envelope, bellows means fixed at one end to the smaller perimeter of the conical shell and at the other end to said end cap, a base plate having a peripheral edge and a free heat radiating surface facing the hollow portion of said shell and extending fully thereacross, said base plate having the marginal edge portion of said free surface in contact with and integrally secured to the supporting surface of said laterally extending flange portion of said annular seat on said conical mounting shell and at its periphery seating against said inner supporting longitudinally extending surface of said depending flange on said conical metallic rigid mounting shell, and a plurality of concentrically spaced cylindrical plates integrally united to said base plate on the surface thereof opposite the free surface of said base plate.

References Cited in the file of this patent UNITED STATES PATENTS 

